Triethylamine → methyl 1-(3-chloropyridin-2-yl)-3-{(E)-2-[5-(trifluoromethyl)-2H-tetrazol-2-yl]vinyl}-1H-pyrazole-5-carboxylate

Participants

Reaction Steps

225 mg (0.54 mmol) of methyl 1-(3-chloropyridin-2-yl)-3-{1-hydroxy-2-[5-(trifluoromethyl)-2H-tetrazol-2-yl]ethyl}-1H-pyrazole-5-carboxylate and methyl 1-(3-chloropyridin-2-yl)-3-{1-hydroxy-2-[5-(trifluoromethyl)-1H-tetrazol-1-yl]ethyl}-1H-pyrazole-5-carboxylate in a ratio of 66:34 were initially charged in 7.0 ml of toluene, 75.3 mg (0.65 mmol) of methanesulphonyl chloride and 166 mg (1.64 mmol) of triethylamine were added at 0° C. and the mixture was stirred at reflux temperature for 10 hours. The reaction mixture was diluted with toluene and washed with sodium bicarbonate solution. The organic phases were dried over magnesium sulphate and the solvent was distilled off under reduced pressure. The residue was chromatographed on silica gel, which gave 132 mg (45% of theory) of methyl 1-(3-chloropyridin-2-yl)-3-{(E)-2-[5-(trifluoromethyl)-2H-tetrazol-2-yl]vinyl}-1H-pyrazole-5-carboxylate and methyl 1-(3-chloropyridin-2-yl)-3-{(E)-2-[5-(trifluoromethyl)-1H-tetrazol-1-yl]vinyl}-1H-pyrazole-5-carboxylate in a ratio of 69:31. (logP: 3.37/3.49; MH+: 400.1; 1H-NMR (400 MHz, CD3CN, δ, ppm): 3.78 (s, 3H), 7.35 (m, 1H), 7.60 (m, 1H), 7.75 (m, 1H), 8.08 (m, 1H), 8.32 (m, 1H), 8.55 (m, 1H).)

Provenance & Evidence